(1) Field of the Invention
The present invention relates to a self-locking hinge apparatus with a single stable state, and more particularly to a hinge apparatus that employs a cam-pattern-like sliding contact between two matching elements for automatically achieving a single stable state.
(2) Description of the Prior Art
A conventional hinge apparatus is general a folding mechanism deployed between two sets of boards, or between one object and another object. The most common used one of those is a free hinge for pivoting a door. Such a type of hinges, usually waiving anchoring components, allows the door to swing freely. In another aspect, such a type of hinge apparatus does not have a local high point in the potential energy diagram, or say a local point of minimum potential energy. While those hinges are applied to fold two boards or objects, no control ability can be provided during the hinging operation.
There are other types of hinge apparatus adopted to be used on swing doors that are constantly closed in normal conditions. Such a type of hinge apparatus generally includes a special pivotal shaft to serve as a common axis and a returning mechanism to provide both a damping force and a return force to close the door. The returning mechanism has one end fastened to the door and another end fastened to the wall at where the door is mounted. When the door is swiveled and opened by an external force, potential energy is stored in the returning mechanism. When the external force is relieved, the returning mechanism releases the potential energy to allow the door to close slowly (due to the function of the damper). However, such types of hinge apparatus tend to gradually get loose and cannot close the door effectively when the dampers are aged. In other words, the minimum-potential energy points of such types of hinge apparatus tends to shift and deviate because of aging of elements.
Viewing previous two types of hinge apparatus set forth above, one does not have a local stable position (such as free hinges), and another has a single local potential energy low point (such as swing doors that are constantly closed). In still another types of hinge apparatus, there are two local minimum-potential energy points, such as hinge apparatus adapted for use on some cabinets or protection covers for button keys of cell phone handsets. They have a torsion spring and a retain structure mounted to selected locations between boards to form two local stable points (i.e. two relative minimum-potential energy points). These two local stable points are generally arranged on a closed and an open location of the targeted object. Take the openable protection cover for button keys of a handset as an example, the hinge apparatus for connecting the cover plate and the handset body usually has two local stable points. One is the closed position of the cover plate over the button keys. Another one is the open position with the cover plate pivotally turned to a selected angle for users to dial phone numbers or to hear the phone. By the same token, the hinge apparatus commonly used for opening doors of cabinets, depending on locations of the cabinet doors, also have a cabinet door open position and a cabinet door closed position.
As discussed previously, an improved hinge apparatus has two local stable points. It can provide control function, and thus has great benefits in applications. Take the cover plate of a handset for example, upon when to open or close the cover plate, users may hold the handset with one hand, and push or lift the cover plate for a selected distance to provide a sufficient external force for making the hinge apparatus to jump from one local stable point to another local stable point, and thereby to change the condition of the cover plate. However, in such type of applications, a torque should be provided to change the condition. In terms of human hand operation characteristics, folding operation of two-board elements, especially for smaller-size devices such as handsets, requires both hands to complete, with one hand to hold the handset and another to exert a torque upon the cover plate. The operation is obviously not convenient, and thus any improvement shall be welcome.
Accordingly, it is a primary object of the present invention to provide a self-locking hinge apparatus that employs cam sliding contact between two co-axial elements to produce a single stable state (or say, equilibrium state) such that it can be stabilized automatically at the predetermined stable state wherever it is initially posed.
The self-locking hinge apparatus with a single stable state according to the invention enables a hinge to turn and stabilize automatically at the single stable state. The hinge apparatus consists of a pivotal shaft, a retaining ring, a stator, a compression spring and a rotor. The retaining ring, the compression spring, the stator and the rotor are arranged in series along the pivotal shaft.
In the present invention, the pivotal shaft of the present invention has a retaining end and a free end. The retaining ring is slidably mounted on the pivotal shaft at the retaining end. The stator is mounted on the pivotal shaft in a slide-able but not rotational manner. The compression spring is mounted on the pivotal shaft between the retaining ring and the stator. The rotor is slidably mounted on the pivotal shaft proximate to the free end, and contacts the stator.
According to one embodiment of the invention, the rotor has a sliding surface facing the stator. The sliding surface is a strictly concave surface (i.e. with a smooth contour allowing an object sliding thereon freely without restriction) surrounding the pivotal shaft. The sliding surface has a lowest point. The stator has a bulged point extending to and pressing onto the sliding surface. When the contact point between the stator and the rotor is initiated at any local point, the compression spring can depress the bulged point of the stator against the sliding surface of the rotor in the axial direction of the pivotal shaft, and the rotor is driven to turn about the pivotal shaft until the bulged point reaching the lowest point of the sliding surface. In other words, the rotation of the rotor stops only when the hinge apparatus has reached the stable state.
In this embodiment, the bulged point of the stator is the most protrusive point of a convex surface.
In order to make the stator sliding along the pivotal shaft without rotating, in one embodiment of the invention, the cross section of the pivotal shaft that holds the stator has at least one chamfered surface, and the stator has a shaft opening complementing the chamfered cross section of the pivotal shaft.
In one embodiment of the invention, the pivotal shaft that holds the stator is a round axle having at least one axial key way, and the shaft opening of the stator has a jutting key matching and engageable with the key way to allow the stator to slide on the pivotal shaft without rotating.
In another embodiment of the invention, the stator has a stator surface facing the rotor. The stator surface is a strictly concave surface surrounding the pivotal shaft. The stator surface has a lowest point. The rotor has a bulged point extending to and pressing onto the stator surface. When the stator and the rotor is initiated at any local point, the compression spring depresses the stator surface of the stator against bulged point of the rotor in the axial direction of the pivotal shaft, and the rotor is driven to turn about the pivotal shaft until the bulged point reaching the lowest point of the stator surface.
In this embodiment, the bulged point of the rotor is the most protrusive point of a convex surface.
The self-locking hinge apparatus with a single stable state according to the invention may be used in the folding apparatus discussed in the background of the invention. The folding apparatus may consist of a first member, a second member and at least one self-locking hinge apparatus located between the first member and the second member. By providing the invention, there is a single stable state between the first member and the second member, and the first member and the second member may be freely folded relative to each other and still reaches the designed stable state.
According to the invention, the pivotal shaft and a respective pivotal shaft""s retention can be connected to a first installation side of the first member, and an outer rim of the rotor and an outer rim of the retaining ring can be connected to a second installation side of the second member. In other words, the hinge apparatus is located between the first installation side and the second installation side to allow the first member and the second member to move and fold over each other.
The folding apparatus according to the invention may also include a latch structure to manipulate another stable state other than aforesaid one, and thus to form an anchoring relationship between the first member and the second member. The anchoring relationship is usually a folding state. The latch structure may include a first latch element on the first member and a corresponding second latch element on the second member. When the first latch element and the second latch element are engaged, the first member is overlapping upon the second member.
In one embodiment of the folding apparatus of the invention, the first latch element of the latch structure is located on the first member, and the second latch element is located on the second member at a location corresponding to the first latch element. The first latch element and the second latch element may not connect with the hinge apparatus. Therefore, the latch structure may be simplified to reduce the complexity of the folding apparatus.
In an embodiment of the folding apparatus of the invention, the latch structure may be simultaneously made with the self-locking hinge apparatus. The implementation can include: a) forming a retaining section on the first member that is extended to the free end of the pivotal shaft as an outer retention of the rotor; b) forming a retaining bulged point located on the rotor facing one side of the free end of the pivotal shaft as the second latch element of the latch structure; c) forming a retaining trough located on the retaining section corresponding to the retaining bulged point as the first latch element; d) further including a compression member located on the retaining section to the latch structure; e) when the retaining bulged point and the retaining trough forming a latched condition, the first member and the second member forming a stacking condition or other folding conditions; and f) when the compression member subjected to a force for releasing the latch condition between the retaining bulged point and the retaining trough, the rotor rotating due to auto cam sliding pair function formed by the stator surface and the sliding surface until the sliding stops, i.e. reaching the stable state of the self-locking hinge apparatus.
In an embodiment of the folding apparatus of the invention, the retaining section may have a second retaining ring to contact the rotor, and the latch structure may include a retaining trough of the first latch element formed on the second retaining ring facing one side of the rotor. The operation of xe2x80x9cthe compression member subjects to a forcexe2x80x9d previously discussed is xe2x80x9cto move the rotor to separate the retaining bulged point from the retaining troughxe2x80x9d. In this embodiment, in order to increase wearing durability of relative sliding between the second retaining ring and the rotor, the second retaining ring is preferably made of metal such as brass or the like.
The foregoing, as well as additional objects, features and advantages of the invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.